Theta Delphini

Theta Delphini
Diagram showing star positions and boundaries of the Delphinus constellation and its surroundings
Location of θ Delphini (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Delphinus
Right ascension 20h 38m 43.98644s[1]
Declination +13° 18′ 54.4543″[1]
Apparent magnitude (V) 5.69[2]
Characteristics
Spectral type K3Ib[3]
U−B color index +1.71[4]
B−V color index 1.509±0.047[2]
Astrometry
Radial velocity (Rv)−15.09±0.13[5] km/s
Proper motion (μ) RA: 3.068[1] mas/yr
Dec.: −0.179[1] mas/yr
Parallax (π)1.5887 ± 0.0738 mas[1]
Distance2,050 ± 100 ly
(630 ± 30 pc)
Details
Mass5.69[6] M☉
Radius125 R☉[7]
88±25[8] R☉
Luminosity2,333+1,103
−748[7] L☉
Surface gravity (log g)1.3[9] cgs
Temperature3,986±170[7] K
Metallicity [Fe/H]+0.22[9] dex
Rotational velocity (v sin i)3.0[10] km/s
Other designations
θ Del, 8 Del, BD+12°4411, GC 28743, HD 196725, HIP 101882, HR 7892, SAO 106342[11]
Database references
SIMBADdata

Theta Delphini, a name Latinized from θ Delphini, is a single[12] star in the northern constellation of Delphinus. It has an apparent visual magnitude of about 5.7,[2] meaning that it is just barely visible to the naked eye under excellent viewing conditions. The distance to this star is approximately 2,050 light years from the Sun based on parallax. It is drifting closer with a radial velocity of −15 km/s.[5]

The stellar classification of Theta Delphini is K3Ib, which means it is a K-type supergiant.[13] These types of stars form when relatively massive (10 to 30 M☉) stars like B-type main sequence stars run out of hydrogen to fuse and start cooling down.[14] It has been described as a super-metal-rich star because of its high metallicity.[9]

  1. ^ a b c d e Cite error: The named reference dr2 was invoked but never defined (see the help page).
  2. ^ a b c Cite error: The named reference Anderson_Francis_2012 was invoked but never defined (see the help page).
  3. ^ Cite error: The named reference bidelman1951 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference Fernie1983 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Famaey_et_al_2005 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference hohle_et_al_2010 was invoked but never defined (see the help page).
  7. ^ a b c Cite error: The named reference messinio_brown_2019 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference vanBelle_et_al_2009 was invoked but never defined (see the help page).
  9. ^ a b c Cite error: The named reference malagnini_et_al_2000 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference deMedeiros_et_al_2002 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Eggleton_Tokovinin_2008 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference Allen was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference Ekström_et_al_2012 was invoked but never defined (see the help page).